Among recent image display apparatuses, there is an apparatus that performs dimming control for adjusting luminance of a light on the basis of an input video signal.
Patent Literature 1 discloses a video display apparatus that performs dimming control for increasing/decreasing luminance of a light source in stages according to a feature amount of an input video signal. This video display apparatus has: a display panel; a backlight light source that illuminates the display panel; a feature amount detection unit that detects the feature amount of the input video signal; and a light source control unit that performs dimming control on the basis of the detected feature amount.
The feature amount detection unit detects an average luminance level that is the feature amount of the input video signal for each screen. The average luminance level of a black screen, which is entirely displayed black, is 0%, while the average luminance level of a white screen, which is entirely displayed white, is 100%.
The light source control unit stores a dimming-up step amount that is a step amount for increasing the luminance in stages, and a dimming-down step amount that is a step amount for decreasing the luminance in stages. In view of adaptation of human eyes to brightness, the dimming-up step amount is set to a value larger than that of the dimming-down step amount.
The light source control unit determines target luminance of the backlight light source on the basis of the average luminance level detected by the feature amount detection unit, and compares the target luminance with a current luminance set value of the backlight light source. When the target luminance is larger than the current luminance set value, the light source control unit increases the luminance set value by the dimming-up step amount to increase the luminance of the backlight light source. On the other hand, when the target luminance is smaller than the luminance set value, the light source control unit decreases the luminance set value by the dimming-down step amount to decrease the luminance of the backlight light source.